BALB/cN strain mice are quite susceptible to 1,2-dimethylhydrazine (DMH) and azoxymethane (AOM) carcinogenesis. However, C57B1/6N strain mice are resistant to DMH, but not to AOM carcinogenesis. There is a sex difference in the response to the colon carcinogens, DMH and AOM. Estrogens play an important role in the shift of target organ from colon to the kidney, mediated by resistance of the female to DMH.